This invention relates in general to vehicle performance sensors and, in particular, to a hydraulic sensor system having a shift point indicator which indicates when to shift the vehicle transmission.
More specifically, but without restriction to the particular use which is shown and described, this invention relates to a hydraulic vehicle performance sensor system that monitors the output of a vehicle torque converter and directs the vehicle operator when and how to shift the vehicle transmission so that optimum performance will be maintained.
As is well known, self-propelled vehicles utilize a transmission to couple the output of an engine to the driving wheels. Some such vehicles, such as crawler tractors, utilize a plurality of gearing ranges to effect the speed and driving force generated by the vehicle. Since each gear range is most efficient to operate at different pre-selected ranges of vehicle operation, the selection of the particular gear range or gearing that will operate the vehicle most efficiently, is best determined in relationship to the output from the vehicle torque converter.
With vehicles such as construction machinery or earth moving equipment, the vehicle transmissions generally are shifted by the machine operator. During operation, the vehicle will operate efficiently while in a given gear if the output of the torque converter is within the range pre-selected for that gear. However, when the output either increases or decreases so that it is no longer within the pre-selected range for that gear, the transmission should be shifted accordingly to maintain the performance of the vehicle at an optimum level.
Since the transmission is manually shifted by the machine operator, in the past operator experience determined when to shift gears with the result that there was no assurance that the gears of the vehicle would be shifted at the proper time. Due to the high level of noise present at the sites where such vehicles are usually operated, the operator in relying on engine sound and "feel," had no accurate means of knowing exactly when to shift gears in order to maintain the optimum performance of the vehicle.
The present invention, therefore, provides a hydraulic system which monitors the output from a vehicle torque converter, and in response to the output speed changes develops a hydraulic pressure that activates or de-activates a plurality of switching devices. These switching devices generate signals to instruct the operator when to shift gears and into which gear the vehicle transmission should be shifted. A panel display is provided to visually indicate this information to the operator, so that he will know exactly when to shift the transmission regardless of the noise on the site. Efficient operation of the vehicle in this manner will both increase the life of the vehicle and reduce the downtime required for vehicle repair.